326 LEPIDOPTERA. 



Indeed the form from which the above description is taken 

 is looked upon as the type merely because it is more common 

 and more generally distributed than the rest, most of which 

 are in some degree local — and of course because it is the 

 form from which the original description of the species was 

 obtained. The varieties in colour and marking seem to 

 extend equally to both sexes, and even with regard to the 

 hind wings there is apparently no strict rule. 



In the forms ranging more particularly around the type 

 the ground colour varies from brownish-buff to pale buff, 

 yellowish-brown, reddish-brown, dull umbreous, and greyish- 

 brown, throughout its area of distribution ; in eastern 

 districts to whitish-brown or even slate-white ; while in the 

 west the more dull umbreous tints prevail, intensified in the 

 west of Ireland to an exceedingly dull sordid umbreous, and 

 blackish-brown. In nearly all cases the colour of the upper 

 part of the thorax follows that of the fore wings. In some 

 of those already mentioned the transverse lines of the fore 

 wings are distinct, as also are the transverse clouded mark- 

 ings, and brown blotches are noticeable between and beyond 

 the stigmata and outside the second line ; in others the lines 

 are distinct but the clouded markings absent, or the lines 

 have disappeared and the clouding has taken possession ; the 

 upper stigmata moreover are white, or white with a brown 

 central cloud, or obscure and devoid of white, or nearly 

 imperceptible ; the nervures range from whitish to yellowish 

 or very pale brown, or are concolorous with the rest of the 

 wings, or very often a portion of the median in the middle 

 area is marked with a slender straight whitish line. In 

 individuals where the dark clouding is absent and the trans- 

 verse lines are conspicuous, the stigmata are sometimes 

 almost obliterated and the first and second lines drawn 

 nearer together, duplicated and formed into a very pretty 

 pattern quite unlike the ordinary forms. In other cases the 

 lint's also disappear, and the fore wings become uuicolorous 

 yellowish-brown, except that a brown spot then shows itself 



